Sanitary Sewer Rehabilitation by Mini-basin to Eliminate SSOs in the Paxton Creek Drainage Basin

The Paxton Creek Interceptor, which serves the municipalities of Susquehanna Township and Lower Paxton Township located in Harrisburg, Pennsylvania, experiences sanitary sewer overflows (SSOs) during extreme wet weather conditions. In order to comply the Pennsylvania Department of Environmental Protection's (PA DEP) request to eliminate the overflows and the Authorities' need to regain capacity for future development, both municipalities have adopted a policy of “total sewer rehabilitation” by mini-basin as a part of their infiltration⊘inflow (I⊘I) reduction programs.Total rehabilitation by mini-basin means that all sewer system components including mainline, manholes, service laterals and buildings sewers located in a mini-basin are repaired so they meet the same acceptance testing standards as new sewers. House inspections to identify and remove suspect inflow sources are also performed at every property in the mini-basin. System components are investigated and repaired during dry weather conditions. Wet weather conditions are used to assess I⊘I removal and verify repairs.Since a mini-basin generally consists of 100 to 300 connections, agreements between property owners and each Authority for investigation and repair of service laterals and building sewers are needed. Both Susquehanna Township Authority and Lower Paxton Township Authority now have policies where observation tees are installed at every property in the mini-basin and all service laterals and building sewers are air tested and repaired or replaced until they pass an air test. This work is completed at the expense of the each Authority and not the property owner.